Heated Mirrors Inoperative

Heated Mirrors Inoperative

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The driver door switch (DDS) and passenger door switch (PDS) supply voltage to the outside rearview mirror heater elements upon receipt of a serial data message from the HVAC module indicating that the rear defrost system is active. The door switch supplies B+ through the driver/passenger mirror heating element supply voltage circuit when a request is seen. Ground is applied through the driver/passenger mirror heating low reference circuit.

Diagnostic Aids

The automatic day-night feature of the inside rearview mirror may mot operate properly or become inoperative due to a short to battery positive voltage in the backup lighting system.

Circuit/System Verification

1. Ignition ON, press the rear window defogger switch. Verify the rear window defogger indicator illuminates.

^ If the rear window defogger indicator does not illuminate.

2. Rear window defogger ON, verify both the left and right outside mirror glass become warm.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector X3 at the appropriate door module.
2. Ignition ON, verify a test lamp does not illuminate between the supply voltage circuit terminal B7 and ground.

^ If the test lamp illuminates, test the supply voltage circuit for a short to voltage.

3. Ignition OFF, test for infinite resistance between the supply voltage circuit terminal B7 and ground.

^ If less than the specified value, test the supply voltage circuit for a short to ground. If the circuit tests normal, test or replace the applicable rearview mirror face.

4. Test for 5-10 ohms of resistance between the supply voltage circuit terminal B7 and the low reference circuit terminal B3.

^ If not within the specified range, test the supply voltage circuit and the low reference circuit for an open/high resistance. If the circuits test normal, test or replace the appropriate rearview mirror face.

5. If all circuits test normal, replace the appropriate door module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Outside Rearview Mirror Glass Replacement